Studies on the influence of in utero and lactational exposure to hormone-modulating pollutants have largely been restricted to studies of cognitive development. Outcome variables in these investigations were not selected to be sensitive to the potential sex hormone-modulating effects of these substances. The proposed epidemiologic study assesses the behavioral sequelae of early developmental exposure to environmental toxicants on human behaviors that exhibit gender-related variation. The study design utilizes an established cohort of subjects (New York State Angler Cohort Study) assembled to assess the association between consumption of contaminated sport fish on both short- and long-term health effects in adults and their offspring. Reproductive outcome data including detailed abstraction of hospital delivery records for mothers who had consumed varying quantities of contaminated fish are available for 3,365 offspring born between 1986-91. The majority of children are now approaching middle childhood, making them old enough to assess a broad spectrum of behavioral sequelae. The study is to be conducted as a postal questionnaire survey in which a parent/guardian serves as an informant of the child's behavior. The behavioral domains targeted for study are those which exhibit gender related variation under normal circumstances, including gender-role behavior of childhood, specific learning disabilities, handedness, and patterns of psychopathologic symptoms. Information on maternal exposure of contaminated fish, long- term and during pregnancy is available to assess dose-response effects. This proposed questionnaire survey represents the initial stage of a long-term research plan involving in-depth developmental investigations including neuropsychological assessments, structured clinical interviews, and more in-depth exposure characterization of the offspring. Such an in-depth follow-up investigation will incorporate research methods adequate to simultaneously evaluate both biological and social-environmental explanations of behavioral sequelae. The overall goal of this pilot project is to assess the relationship between toxicant exposures (pre-and postnatal) and behavioral outcomes selected because they are susceptible to perturbation of sex hormone physiology at sensitive periods of the sexual differentiation process and at concentrations that are not maternally toxic.